The Mercenary Way by Tory Richards
Kidnapped and imprisoned, Sarah Reynolds needs all the help she can get – but soldier-of-fortune Clint Becker is just a different kind of danger. When a ruthless gem smuggler mistakes Sarah for her best friend, Susan, she’s kidnapped and stashed on an island. Her only hope of rescue is Susan’s cousin Clint – a man whose my-way-or-else attitude is as infuriating as his muscular body is distracting.